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MAC address lookup: how to identify a device

A MAC address is a 48-bit label burned into a network adapter. The first half names the manufacturer, so you can often tell whether an unknown device on your network is a phone, a printer or something you didn't expect.

Look up a MAC address

Enter a full MAC address or just the first six hex digits:

How a MAC address is built

A MAC address is six bytes, written as twelve hex digits. Common formats are 00:1B:63:84:45:E6, 00-1B-63-84-45-E6 and 001B.6384.45E6. They all mean the same address.

  • First three bytes (00:1B:63): the OUI, the Organizationally Unique Identifier. The IEEE assigns it to a manufacturer. This is what a lookup uses.
  • Last three bytes (84:45:E6): assigned by the manufacturer to the individual adapter.

The OUI names the company that made the network chip, which isn't always the brand on the box. A laptop might report Intel, a router might report the maker of its Wi-Fi module.

Why a lookup sometimes finds nothing

The second-lowest bit of the first byte is the locally administered bit. When it's set, the address was made up in software and no manufacturer is registered for it. You can recognise these: the second hex digit is 2, 6, A or E, as in 3A:... or DA:....

This is now normal. Phones, tablets and laptops use a random private address for each Wi-Fi network, so the address a router shows for your phone isn't the one on the chip. Turn that feature off for a network if you need a stable address, for example for a MAC filter.

Find the MAC address of your own device

  • Windows: run ipconfig /all and read Physical Address.
  • macOS: run ifconfig en0 | grep ether, or open Network settings.
  • Linux: run ip link and read the link/ether line.
  • Phones: open Wi-Fi details in the settings app.

Find unknown devices on your network

  1. Open your router's list of connected devices, or run arp -a on a computer to list neighbours.
  2. Look up the OUI of each address you don't recognise.
  3. Match it to something you own. A smart TV, printer or games console often shows its maker's name.
  4. If one stays unknown and the address is private, turn your devices' Wi-Fi off one by one to see which entry disappears.

A MAC address works only inside the local network segment. It's never sent across the internet, and it doesn't reveal where you are. To tell your private and public addresses apart, read how to find your IP address.

Frequently asked questions

What is an OUI?

The Organizationally Unique Identifier is the first three bytes (six hex digits) of a MAC address. The IEEE assigns it to a manufacturer, so it identifies the company that made the network chip, not the model.

Why does a MAC lookup say unknown or find nothing?

Most often the address is a private, randomised one. Modern phones, tablets and laptops use a random MAC per Wi-Fi network, and those addresses have the locally administered bit set, so no manufacturer is registered for them.

Can a MAC address be changed?

Yes. It can be set in software, and many systems now randomise it on purpose. A MAC address is a label, not proof of identity.

Does a MAC address reveal my location?

No. A MAC address is only used on the local network segment and is not routed across the internet.